Atomic weight of the element: 14.0438+0.
Number of protons: 7
Neutron number: 7
Atomic number: 7
Period: 2
Number of families: Virginia
Electron shell distribution: L2-K5
Nitrogen is a colorless and odorless gas with a melting point of -209.86℃, a boiling point of-195.8℃, a gas density of 1.25046 g/L, a critical temperature of-146.95℃ and a critical pressure of 33.54 atm.
Nitrogen fertilizer is the main component of protein, which plays an important role in the growth of stems and leaves and the development of fruits, and is the nutrient element most closely related to yield. Before the first ear expanded rapidly, the plant's absorption of nitrogen gradually increased.
Later, in the whole growth period, especially in the peak period of mushroom production, the absorption reached its peak. When the soil is short of nitrogen, the plants are short, the leaves are yellow, the differentiation of flower buds is delayed, the number of flower buds is reduced, the fruit is small, there is little or no fruit setting, the yield is low and the quality is poor. When there is too much nitrogen, plants will grow in vain and flourish, which will easily lead to a large number of falling flowers, stagnant fruit development, reduced sugar content and weakened plant disease resistance. The demand for nitrogen fertilizer in tomato seedling stage is indispensable and should be properly controlled to prevent excessive growth; In the fruit-bearing period, Qin Ying should apply more chemical fertilizers to ensure the needs of fruit development. Nitrogen is a harmless gas, because its chemical activity is stable and it is not easy to react with other substances. In the air, the gas volume of nitrogen accounts for 78%, which mainly plays the role of maintaining atmospheric pressure. Otherwise, the atmospheric pressure is too weak, which is not conducive to human survival. A typical example is the Qinghai-Tibet Plateau, where the atmosphere is thin and the oxygen content is low. Unless the local people, it is difficult to adapt, prone to altitude sickness.
Carbon compounds are generally obtained from fossil fuels, and then separated and further synthesized into various products needed for production and life, such as ethylene and plastics.
Carbon has various forms, such as crystal element carbon, such as diamond and graphite; There is amorphous carbon such as coal; There are complex organic compounds such as animals and plants; Carbonate, such as marble. The physical and chemical properties of elemental carbon depend on its crystal structure. High hardness diamond and soft graphite have different crystal structures, each with its own appearance, density and melting point.
At room temperature, elemental carbon is chemically inactive and insoluble in water, dilute acid, dilute alkali and organic solvents. React with oxygen at different high temperatures to generate carbon dioxide or carbon monoxide; Among halogens, only fluorine can react directly with elemental carbon; Under heating, elemental carbon is easily oxidized by acid; At high temperature, carbon can also react with many metals to form metal carbides. Carbon is reducible and can be used to smelt metal at high temperature.
The chemical formula you said is calcium cyanate, which reacts with water to mainly produce calcium hydroxide.
Nitrogen is a colorless and odorless gas with a melting point of -209.86℃, a boiling point of-195.8℃, a gas density of 1.25046 g/L, a critical temperature of-146.95℃ and a critical pressure of 33.54 atm.
Nitrogen fertilizer is the main component of protein, which plays an important role in the growth of stems and leaves and the development of fruits, and is the nutrient element most closely related to yield. Before the first ear expanded rapidly, the plant's absorption of nitrogen gradually increased.
Later, in the whole growth period, especially in the peak period of mushroom production, the absorption reached its peak. When the soil is short of nitrogen, the plants are short, the leaves are yellow, the differentiation of flower buds is delayed, the number of flower buds is reduced, the fruit is small, there is little or no fruit setting, the yield is low and the quality is poor. When there is too much nitrogen, plants will grow in vain and flourish, which will easily lead to a large number of falling flowers, stagnant fruit development, reduced sugar content and weakened plant disease resistance. The demand for nitrogen fertilizer in tomato seedling stage is indispensable and should be properly controlled to prevent excessive growth; In the fruit-bearing period, Qin Ying should apply more chemical fertilizers to ensure the needs of fruit development. Nitrogen is a harmless gas, because its chemical activity is stable and it is not easy to react with other substances. In the air, the gas volume of nitrogen accounts for 78%, which mainly plays the role of maintaining atmospheric pressure. Otherwise, the atmospheric pressure is too weak, which is not conducive to human survival. A typical example is the Qinghai-Tibet Plateau, where the atmosphere is thin and the oxygen content is low. Unless the local people, it is difficult to adapt, prone to altitude sickness.
Carbon compounds are generally obtained from fossil fuels, and then separated and further synthesized into various products needed for production and life, such as ethylene and plastics.
Carbon has various forms, such as crystal element carbon, such as diamond and graphite; There is amorphous carbon such as coal; There are complex organic compounds such as animals and plants; Carbonate, such as marble. The physical and chemical properties of elemental carbon depend on its crystal structure. High hardness diamond and soft graphite have different crystal structures, each with its own appearance, density and melting point.
At room temperature, elemental carbon is chemically inactive and insoluble in water, dilute acid, dilute alkali and organic solvents. React with oxygen at different high temperatures to generate carbon dioxide or carbon monoxide; Among halogens, only fluorine can react directly with elemental carbon; Under heating, elemental carbon is easily oxidized by acid; At high temperature, carbon can also react with many metals to form metal carbides. Carbon is reducible and can be used to smelt metal at high temperature.
Chemical symbol: c
Atomic weight of the element: 12.438+0.
Number of protons used: 6
Atomic number: 6
Period: 2
Family: IVA
Electron shell distribution: 2-4
Atomic volume: 4.58 cc/mol
Atomic radius (calculated value): 70(67)pm
* * * Price radius: 77 pm
Van der Waals radius: 170 pm
Electronic configuration: 1 s222p 2
Electronic arrangement of each energy level: 2, 4
Oxidation value (oxide): 4,3,2 (weakly acidic)
Color and appearance: black (graphite), colorless (diamond) charcoal, activated carbon, carbon black.
State of matter: solid state
Physical properties: diamagnetism
Melting point: about 3727℃ (3550℃ for diamonds).
Boiling point: about 4827℃ (sublimation)
Molar volume: 5.29× 10-6m3/mol.
Content of elements in the sun: (ppm) 3000.
Element content in seawater: (ppm) Pacific surface 23
Content of elements in the crust: (ppm)4800.
Mohs hardness: graphite 1-2, diamond 10.
Oxidation state: mainly -4,, C+2, C+4 (and other oxidation states).
Chemical bond energy: (kj/mol) c-h 411c-c348c = c 614c ≡ c839c = n 615c ≡ n891c =
Cell parameter: a = 246.4pmb = 246.4pmc = 671.1pmα = 90β = 90γ =120.
Ionization energy: (kj/mol) m-m+1086.2m+-m2+2352m2+-m3+4620m3+-M4+6222m4+-M5+37827m5+-M6+47270.
Element density: 3.513g/cm3 (diamond) and 2.260g/cm3 (graphite, 20℃).
Electronegativity: 2.55 (Pauling scale)
Specific heat: 710j/(kg k)
Electrical conductivity: 0.06 1× 10-6/ (m ohms)
Thermal conductivity:129 w/(m k) first ionization energy 1086.5 kJ/mol second ionization energy 2352.6 kJ/mol third ionization energy 4620.5 kJ/mol fourth ionization energy 6222.7 kJ/mol fifth ionization energy 37831mol.
Bonding: carbon atoms are generally tetravalent and need four single electrons, but its ground state has only two single electrons, so hybridization is always needed when bonding. The most common hybridization method is sp3 hybridization, which makes full use of four valence electrons, evenly distributed in four orbits, and belongs to isotropic hybridization. This structure is completely symmetrical, and it is a stable σ bond after bonding, and it is very stable without the repulsion of lone electron pairs. All the carbon atoms in diamond are combined in this way. The carbon atoms of alkanes also belong to this category.
According to requirements, carbon atoms can also be hybridized with sp2 or sp. Both of these methods appear in the case of re-bonding, and the non-hybridized P orbitals are perpendicular to the hybridized orbitals, forming π bonds with the P orbitals of adjacent atoms. The carbon atom connecting the double bond in olefins is sp 2 hybridization. Because sp2 hybridization can make the atom * * * plane, when multiple double bonds appear, all P orbitals perpendicular to the molecular plane may overlap each other, forming a * * * yoke system. Benzene is the most typical yoke system, which has lost some properties of double bonds. All the carbon atoms in graphite are in a large yoke system, one for each layer.
[Edit this paragraph] Isotopes of carbon
There are twelve known isotopes * * *, ranging from carbon 8 to carbon 19, of which carbon 12 and carbon 13 are stable, while others are radioactive. Among them, the half-life of carbon 14 is more than 5000 years, and others are less than half an hour. In the nature of the earth, carbon 12 accounts for 98.93% of all carbon, while carbon 13 accounts for 1.07%. The atomic weight of C is the weighted average of carbon 12 and 13, and 12.05438+0 is generally taken in the calculation. Carbon 12 is the scale of moles defined in the international system of units, and the number of atoms contained in 12g carbon 1 2 is1mole. Carbon 14 is widely used to date antiquities because of its long half-life.
[Edit this paragraph] Forms of elemental carbon
The two most common simple substances are high hardness diamond and soft and greasy graphite, and their crystal structures and bonding types are different. Each carbon of a diamond is tetrahedrally 4 coordinated, similar to aliphatic compounds; Each carbon of graphite is a triangle 3 coordination, which can be regarded as infinite benzene rings fused together.
The chemical properties of elemental carbon are relatively stable at room temperature and insoluble in water, dilute acid, dilute alkali and organic solvents.
1. Diamond
Diamond structure diagram
The strongest carbon structure, in which carbon atoms are arranged in the form of crystal structure, and each carbon atom is closely combined with the other four carbon atoms to form a spatial network structure, and finally a solid with high hardness and poor activity is formed.
The melting point of diamonds exceeds 3500℃, which is equivalent to the surface temperature of some stars.
Main functions: decorations, cutting metal materials, etc.
2. Graphite
Graphite is a dark gray, metallic and opaque fine scale-like solid. Soft, greasy and has excellent electrical conductivity. The carbon atoms in graphite are bonded together in a plane layered structure, and the bonding between layers is fragile, so the layers are easily separated by sliding.
Main functions: making pencils, electrodes, trolley wires, etc.
3. Fullerenes, C60, C72, etc. )
C60 1985 was discovered by scientists at Ross University in Texas, USA.
The carbon atoms in fullerenes are bonded together in a spherical dome structure.
4. Other carbon structures
Hexagonal diamonds (also known as hexagonal diamonds) have the same bond type as diamonds, but the atoms are arranged in a hexagon.
Graphene (single layer graphite)
Carbon nanotubes (carbon nanotubes, with typical layered hollow structure characteristics)
Monoclinal superhard carbon (M- carbon, high pressure phase of graphite after low temperature, with monoclinic structure, and its hardness is close to that of diamond)
Amorphous carbon (amorphous, not really alien, internal structure is graphite)
Zhao graphite (Chaoite, that is, pyrophyllite, is produced when graphite collides with meteorites, and the atoms are arranged in a hexagonal shape).
Mercury tetrahedrite structure (an imaginary structure, the hexagonal layer is twisted into a "negative curvature" saddle shape due to the appearance of heptagons)
Carbon fiber (fiber made of small pieces piled up in long chains)
Carbon aerogels (carbon aerogels, porous structure with extremely low density, similar to the well-known silicon aerogel).
Carbon nano-foam (cobweb-like, with fractal structure, density is 1% of that of carbon aerogels, with ferromagnetism).
Hexagonal diamond monolayer graphite and carbon nanotubes monoclinic superhard carbon (M- carbon)
[Edit this paragraph] Compounds of carbon element
Among the compounds of carbon, only the following compounds belong to inorganic substances:
Oxides and sulfides of carbon: carbon monoxide (CO), carbon dioxide (CO2), carbon disulfide (CS2), carbonate, bicarbonate, cyanide, a series of pseudohalogens and their pseudohalides, pseudohalogens: cyanogen (CN)2, cyanogen oxide and thiocyanate.
Other carbon-containing compounds are organic compounds. Because the bonds formed by carbon atoms are relatively stable, the number and arrangement of carbon and the types and positions of substituents in organic compounds are very arbitrary, which leads to the phenomenon of a large number of organic substances. At present, among the compounds discovered by human beings, organic matter accounts for the vast majority.
The properties of organic compounds are quite different from those of inorganic compounds. They are generally flammable and insoluble in water, and their reaction mechanism is complicated. Now they have formed an independent branch-organic chemistry. Distributed carbon exists in nature (such as diamond and graphite) and is the main component of coal, oil, asphalt, limestone, other carbonates and all organic compounds, and its content in the earth's crust is about 0.027% (the content calculated by different analytical methods is different). The elements with the highest content in the crust are O 46.6%, Si 27.7% and Al 8. 1% in turn.
Carbon is the largest element in the dry weight of organisms. Carbon also circulates in the earth's atmosphere and stratosphere in the form of carbon dioxide. Carbon exists in most celestial bodies and their atmospheres.
[edit this paragraph] combustion heat equation of carbon combustion combustion calorific value
Combustion of 1 carbon in oxygen: product: carbon dioxide; Color of light or flame: white light.
2 Carbon burns in air: products: carbon dioxide (oxygen is sufficient) and carbon monoxide: (oxygen is insufficient); Color of light or flame: red heat.
Combustion heat equation: c (s)+O2 (g) = CO2 (g) △ h =-393.5kJ/mol.
4 Combustion calorific value: 393.5kJ/mol.
[Edit this paragraph] The discovery history of carbon
Diamonds and graphite have been known since prehistoric times.
Fullerenes were discovered in 1985, and then a series of carbon elements with different arrangements were discovered.
Isotope carbon 14 was discovered by American scientists Martin Carmen and Samuel Rubin in 1940.
Hexagonal diamonds were discovered by American scientists Gafford Rongdile and Yusula Marvin in 1967.
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